A. Field of the Invention
This invention generally relates to a method of aligning an X-ray source and an X-ray detector, and more particularly, to aligning a linear array X-ray detector in a automated, digital X-ray inspection system for evaluating aircraft engine gas turbine blades.
B. Discussion
The manufacture of high performance, fuel efficient aircraft turbine blades has led to the development of turbine blades containing complex interior passages and openings to the blade surface for blade cooling. Performance and life of the blades is dependent upon the manufacture of these interior structures within specifications. A high possibility exists for blade failure because of machinery damage, incompletion of mission, and hazard to personnel. For these reasons 100% inspection of turbine blades is important to the public and a higher automated digital X-ray inspection system has long been desired.
An X-ray inspection station for evaluating the turbine blades includes an X-ray machine and an X-ray image system. The X-ray machine includes a X-ray source for directing X-ray beam radiation, a linear array X-ray detector for receiving the radiation and producing electrical signals representative thereof, manipulating parts, and means for controlling the flow of parts to the X-ray machine. The X-ray image system includes computer hardware and software for acquiring X-ray data, image generation, archiving, displaying, performing computations, and controlling the X-ray machine. The system is a production type automated inspection module capable of detecting internal flaws in jet engine single turbine blades. The X-ray inspection system manually or automatically performs X-ray computer tomography or digital fluoroscopy inspection on the gas turbine engine blades. Any blade is loaded into a gripper and then placed on a conveyor belt. The blade and gripper are then automatically advanced to a part inspection station. A part manipulator moves the blade and gripper from the conveyor inspection system and moves the gripper and blade into the X-ray beam. The part manipulator has two axes of movement, a vertical translation perpendicular to the X-ray beam and a rotational movement about the perpendicular axis. The part manipulator moves the blade linearly for generating a digital fluoroscopy image. The part manipulator rotates the blade in the X-ray beam for generating a computed tomography. After the scan is complete the blade is returned to the conveyor. As the blades are advanced by the conveyor they are moved to an unload station where they are removed by an operator.
It is an object of the present invention to provide a method for aligning the linear array X-ray detector to the directed beam from the X-ray source.